Conventionally, an illumination apparatus including a plurality of DC power supply circuits being controlled individually has been proposed (see, e.g., Japanese Unexamined Patent Application Publication No. 2009-154748). Each of the DC power supply circuits turns on a light source such as an LED (Light Emitting Diode) array. That is, by individually controlling the DC power supply circuits, it is possible to vary the state of the light source such as a change in light output or an on/off state for each of the DC power supply circuits. For example, if a light color or an illumination range is different for each of the light sources, by individually controlling each of the DC power supply circuits as described above, it is possible to flexibly change the light color obtained by mixing colors or the illumination range as a whole.
Further, there has been also proposed an illumination apparatus in which a plurality of light sources is connected to one DC power supply circuit and is switched one by one.
When a difference in rated voltage between the plurality of light sources connected to one DC power supply circuit is large, if it is switched from the light source having a high rated voltage to the light source having a low rated voltage, excessive electrical stress may be applied to the light source immediately after the switching.